4QGT

The Crystal Structure of Human IgG Fc Domain with Enhanced Aromatic Sequon

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.99 Å
  • R-Value Free: 0.326 
  • R-Value Work: 0.298 
  • R-Value Observed: 0.299 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history. 


Literature

Stabilizing the CH2 Domain of an Antibody by Engineering in an Enhanced Aromatic Sequon.

Chen, W., Kong, L., Connelly, S., Dendle, J.M., Liu, Y., Wilson, I.A., Powers, E.T., Kelly, J.W.

(2016) ACS Chem Biol 11: 1852-1861

  • DOI: 10.1021/acschembio.5b01035
  • Structures With Same Primary Citation

  • PubMed Abstract: 

    • Monoclonal antibodies (mAbs) exhibiting highly selective binding to a protein target constitute a large and growing proportion of the therapeutics market. Aggregation of mAbs results in the loss of their therapeutic efficacy and can result in deleter ...

    Monoclonal antibodies (mAbs) exhibiting highly selective binding to a protein target constitute a large and growing proportion of the therapeutics market. Aggregation of mAbs results in the loss of their therapeutic efficacy and can result in deleterious immune responses. The CH2 domain comprising part of the Fc portion of Immunoglobulin G (IgG) is typically the least stable domain in IgG-type antibodies and therefore influences their aggregation propensity. We stabilized the CH2 domain by engineering an enhanced aromatic sequon (EAS) into the N-glycosylated C'E loop and observed a 4.8 °C increase in the melting temperature of the purified IgG1 Fc fragment. This EAS-stabilized CH2 domain also conferred enhanced stability against thermal and low pH induced aggregation in the context of a full-length monoclonal IgG1 antibody. The crystal structure of the EAS-stabilized (Q295F/Y296A) IgG1 Fc fragment confirms the design principle, i.e., the importance of the GlcNAc1•F295 interaction, and surprisingly reveals that the core fucose attached to GlcNAc1 also engages in an interaction with F295. Inhibition of core fucosylation confirms the contribution of the fucose-Phe interaction to the stabilization. The Q295F/Y296A mutations also modulate the binding affinity of the full-length antibody to Fc receptors by decreasing the binding to low affinity Fc gamma receptors (FcγRIIa, FcγRIIIa, and FcγRIIIb), while maintaining wild-type binding affinity to FcRn and FcγRI. Our results demonstrate that engineering an EAS into the N-glycosylated reverse turn on the C'E loop leads to stabilizing N-glycan-protein interactions in antibodies and that this modification modulates antibody-Fc receptor binding.

    Organizational Affiliation: 

    The Skaggs Institute for Chemical Biology, The Scripps Research Institute , La Jolla, California 92037, United States.



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Hepatitis B virus receptor binding protein
A, B
233Homo sapiensMutation(s): 2 
Find proteins for Q6PYX1 (Homo sapiens)
Go to UniProtKB:  Q6PYX1
Protein Feature View
  • Reference Sequence
Small Molecules
Ligands 5 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAG
Query on NAG
Download CCD File 
A, B
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N		 Ligand Interaction
BMA
Query on BMA
Download CCD File 
A, B
BETA-D-MANNOSE
C6 H12 O6
WQZGKKKJIJFFOK-RWOPYEJCSA-N		 Ligand Interaction
MAN
Query on MAN
Download CCD File 
A, B
ALPHA-D-MANNOSE
C6 H12 O6
WQZGKKKJIJFFOK-PQMKYFCFSA-N		 Ligand Interaction
FUC
Query on FUC
Download CCD File 
B
ALPHA-L-FUCOSE
C6 H12 O5
SHZGCJCMOBCMKK-SXUWKVJYSA-N		 Ligand Interaction
GOL
Query on GOL
Download CCD File 
B
GLYCEROL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N		 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.99 Å
  • R-Value Free: 0.326 
  • R-Value Work: 0.298 
  • R-Value Observed: 0.299 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 154.072α = 90
b = 49.19β = 104.21
c = 75.536γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
PHASERphasing
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2015-04-08
    Type: Initial release
  • Version 1.1: 2016-11-23
    Changes: Database references